Recently, with an increase in a communication amount of wireless communication, data communication using a high-frequency band of 30 GHz or more has been performed. In such a situation, as a communication scheme used to suppress attenuation of radio waves, an array synthesis scheme has attracted attention. The array synthesis scheme is a technology that suppresses attenuation of radio waves so that the directivity of each antenna is enhanced by outputting output signals each having a certain phase through a plurality of antennas so as to combine the output signals.
In a wireless communication device that employs the array synthesis scheme, a vector synthesis type phase shifter may be used in order to obtain a certain phase. The vector synthesis type phase shifter includes two amplifiers in each of which the gain is variable and that respectively amplify two signals that have been obtained by dividing an input signal, and the phase of which are different from each other by 90°, and generates an output signal having a certain phase by combining the outputs from the two amplifiers. The phase of the output signal is changed so that the gains of the two amplifiers provided in the vector synthesis type phase shifter are controlled.
As a technology that obtains a certain phase using the vector synthesis type phase shifter, a related art is known in which four amplifiers the phases of which are different from each other by 90° are provided in the vector synthesis type phase shifter, and outputs from certain two amplifiers of the four amplifiers are combined to generate an output signal. As technical literatures of the related art, there is a Japanese Laid-open Patent Publication No. 2009-171469.